4K dual GPU or wait?

I am working towards pushing visuals to the limit on my UE4 project, and this would mean taking things up to play in realtime on a 4K monitor. However, from what I have read online, even with my GTX980, I would struggle to get high framerates on anything above 1440p. The common solution is to get another GPU and run them both in SLI, however, I have heard that UE4 works best on a single card! Are there benefits for multiple cards when working with UE4 or would it be better to wait until single cards are powerful to drive games at 4K with ultra settings?

There’s a response from [March '14][1], when i last checked.

From reading reviews, you need a good 3 to 4 GB of VRAM to get real ultra on 1080p/1440p with great visuals, so a true 4k card would need at least 16GB of VRAM (assuming it scales linearly, id assume its worse and need 20GB+). And to be honest, ultra settings on 1080p/1440p needing magic 3-4GB are probably because that’s how much they have. Anyway, just saying 2 or 3 or 4 x 980s in SLI still always get you 4GB of VRAM. They never get added together in any of the SLI forms. (From what i’ve read).

I’m more hoping a 960 or 970 or just previous card can be left in system to speed up lighting, shader,… rebuilds. Something cheaper than buying a full fledged X99 system. Like how you can dedicate a GPU for PhysX.

Does the UE4 engine support SLI? - Programming & Scripting - Epic Developer Community Forums

I saw that response but I was wondering if it had changed since then!

Thanks for the insight on the SLI stuff, I think it is to play the waiting game before the monster cards come out that can properly handle 4K! Still I have high hopes, I remember when 128 MB RAM was top tier stuff! Hopefully we get the same fast upgrades for VRAM.

No SLI for UE4